Load-engaging device for hoisting concrete building elements

ABSTRACT

With a view to being placed about the head of a lifting bolt placed in a hemispherical recess in a concrete building element, the load-engaging device for hoisting the concreted building element comprises a body having a spherical surface. An arm having an abutment surface protrudes from the body and is used for turning the body in the recess. The body further comprises an inverted T-shaped slot extending through approximately 180 degrees along the spherical surface of the body. This T-shaped slot is adapted to receive the head of the lifting bolt. A central slot extends approximately diametrically through the body and opens into the inverted T-shaped slot. A bolt placed eccentrically about the abutment surface extends across the central slot and is secured in bores in the body. A connecting member is placed in the central slot and retained by the bolt. This load-engaging device prevents the head of the lifting bolt from being released from the device when the concrete element is being hoisted.

TECHNICAL FIELD

The invention relates to a load-engaging device for hoisting concretebuilding elements.

BACKGROUND ART

A device of the kind referred to above is described in DE PatentPublications Nos. 3,012,278 and 3,012,280, relating to an apparatus forsuspending a concrete body in a hoisting apparatus. In this apparatus,the load-engaging tackle comprises a suspending shackle with a link eyeextending through a link bore through the middle of the body, and aninadvertent release of the head of the lifting bolt is prevented by themanipulating arm abutting against a rib in this suspending shackle, ifthe situation entails a risk of such a release.

DISCLOSURE OF THE INVENTION

It is the object of the invention to provide a load-engaging device ofthe kind referred to initially that allows forces to be exerted on thelifting bolt at an oblique angle of e.g. 45 degrees with the surface ofthe concrete element without risk of the head of the lifting bolt beingreleased, said device at the same time being capable of use with varioushoisting-connecting means.

Since the load-engaging device according to the invention after havingbeen attached to the lifting bolt, but before the lifting of theconcrete element, is freely rotatable about this bolt in thehemispherical recess, it is always possible, with a view to obliqueforces being exerted subsequently on the device, to turn themanipulating arm so as to make it face in the direction, from which theforce is exerted, and since the force is transmitted to the boltsituated eccentrically relative to the abutment surface of themanipulating arm, this abutment surface will be pressed against thesurface of the concrete element, so that it is no longer possible toturn the body in the recess to that position, in which the head of thelifting bolt can be released. At the same time, it is possible to attachvarious hoisting-connecting means to the bolt extending through thecentral slot in the body.

If the load-engaging device according to the invention constitutes apart of a ready-made hoisting sling comprising a chain, the end link ofthe chain is retained in the central slot by a bolt.

If the connecting means is a hook or a shackle, then an universal jointis used to engage the shackle or hook.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed portion of the present description, theinvention will be explained in more detail with reference to theexemplary embodiment of a load-engaging device according to theinvention shown in the drawings, in which

FIG. 1 shows the load-engaging device in section along the line I--I inFIG. 2a,

FIG. 2a shows the device as viewed in the direction of the arrow II inFIG. 1,

FIG. 2b shows the device as viewed in the direction of the arrow III inFIG. 1,

FIG. 3 shows the device being attached to a lifting bolt,

FIG. 4 in the same manner as in FIG. 1 shows a chain secured to thedevice, and

FIG. 5 in the same manner as in FIGS. 1 and 3 shows the load-engagingdevice connected to the eye of a shackle through a universal joint.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1, 3, and 4 show a load-engaging device according to theinvention, generally designated by the reference numeral 1, as shown inthe drawing placed in a securing manner about the head 2 and a part ofthe stem 3 on a lifting bolt embedded in a hemispherical recess 4 in aconcrete building element 5, of which only a part is shown. The device 1comprises a body 6 symmetrical about a central plane corresponding tothe sectional line I--I in FIG. 2a, in the form of a central segment ofa sphere with a slightly smaller diameter than the hemispherical recess4, having a protruding manipulating arm 7 with an abutment surface 8extending radially relative to the body 6, said surface 8 being adaptedto abut against the surface 9 of the concrete element 5, when the device1 is placed in a securing manner on the head 2 of the lifting bolt 2,3.When the device 1 is to be placed about the head 2 on a lifting bolt2,3, the arm 7 is used for turning the body 6 relative to the head 2 tothe position shown in FIG. 3.

The body 6 comprises an inverted T-shaped slot 10 extending along itsspherical surface and adapted to receive the head 2 and a part of thestem 3 of the lifting bolt. In the securing position for the liftingbolt 2,3, its stem 3 forms an angle of about 90 degrees with theabutment surface 8 on the arm 7 abutting against the surface 9 on theconcrete element 5, and the head 2 on the lifting bolt is positioned atthe inner, closed end of the T-slot 10. At the other end of the latter,there is a cut-out 11 making it possible to introduce the head 2 of thelifting bolt in the part of the T-slot 10 corresponding to the crossbeamin the T, a part of the stem 3 of the lifting bolt being introduced inthe part of the slot 10 corresponding to the vertical beam in the T,when the load-engaging device 1 is in the position shown in FIG. 3 inthe hemispherical recess 4 in the concrete element 5. In the sameposition, the lifting bolt 2,3 may be released from the load-engagingdevice 1.

A slot 12 for receiving a chosen connecting means in a manner to beexplained below extends centrally and substantially diametrically in thebody 6 and opens into the T-slot 10. Mutually aligned bores 13 aresituated eccentrically in the body 6 and diametrically opposite to theretaining position for the lifting bolt 2,3 shown in FIG. 1, i.e.penetrating the body and the slot 12 at right angles in a diametralplane through the body 6 at right angles to the abutment surface on themanipulating arm 7; these bores 13 are adapted to receive a bolt 14 forsecuring the connection means, the bolt 14 being removably secured inthe body 6 by means of a pin (not shown). Finally, the body 6 comprisesan incision 15 above and parallel to the abutment surface 8, thefunction of which will be explained below with reference to FIG. 5.

FIG. 4 shows the load-engaging device according to the invention inoperation with a chain 16 as connecting means, the chain 16 beingsecured to the body 6 by having its end link 17 placed within the slot10, the bolt 14 having subsequently been inserted through this link 17.

When, as shown in FIG. 4, there is an oblique pull in the chain 16, thispull will exert a turning moment on the body 6, causing the abutmentsurface 8 on the arm 7 to be pressed firmly against the surface 9 on theconcrete element 5. Thus, there is no possibility, when the concreteelement 5 is being lifted, that the body 6 can turn away from theposition shown in FIG. 4 to the release position shown in FIG. 3.

FIG. 5 shows an embodiment of the load-engaging device according to theinvention intended for use with connecting means like a hook or ashackle (not shown). In this embodiment, a lug 18 on a universal jointgenerally designated 19 is introduced in the slot 12 in the body 6 andretained therein by having the bolt 14 extending through a bore in thelug 18. Transversely to the lug 18, the universal joint 19 comprises afork, through the legs 20 of which there are mutually aligned boresreceiving a bolt 21, likewise extending through a bore in a lug 22having an eye 23 for receiving a shackle or a hook. As shown, theincision 15 allows the universal joint 19 and with it the lug 22 and theeye 23 to be turned about the bolt 14 to a position, in which they forman angle of approximately 45 degrees with the surface 9 of the concreteelement 5. When the hook or the shackle as shown in FIG. 5 pullsobliquely upwards on the eye 23, the same force relationships apply asexplained above with reference to FIG. 4, and the body 6 cannot turnaway from the retaining position shown to the release position for thehead 2 on the lifting bolt 2,3 shown in FIG. 3.

I claim:
 1. Load-engaging device (1) to be placed securingly about a head (2) on a lifting bolt having a head and a stem (2, 3) embedded in a hemispherical recess (4) in a concrete building element (5) for hoisting the latter with the aid of a hoisting apparatus and the load-engaging device comprising a body (6) that is symmetrical about a central plane (I--I), having a spherical surface, and fitting into said hemispherical recess (4), said body (6) comprising a protruding manipulating arm (7) with an abutment surface (8) extending substantially radially relative to the body (6), the latter also comprising an inverted T-shaped slot (10) extending through approximately 180 degrees along the spherical surface of the body (6) and adapted to receive the head (2) and a part of the stem (3) of said lifting bolt (2, 3) and the inverted T-shaped slot (10) having a retaining position to retain the latter in a position, in which the stem (3) forms an angle of approximately 90 degrees with the abutment surface (8) on the arm (7), said inverted T-shaped slot (10) at its end opposite to the retaining position for the lifting bolt (2, 3) having a cut-out (11), through which the head (2) of the lifting bolt (2, 3) may be inserted in and removed from said inverted T-shaped slot (10), characterized ina) that a central slot (12) extends centrally and substantially diametrically in the body (6) and opens into the inverted T-shaped slot (10), and b) that mutually aligned bores (13) for receiving a bolt (14) for attachment of a connecting means to the body (6) extend within the region of said slot (12) eccentrically in the body (6) and substantially diametrically opposite the retaining position for the lifting bolt (2, 3).
 2. Load-engaging device according to claim 1, characterized in that the connecting means is a chain (16) having an end link (17), the end link (17) of which is retained in the central slot (12) by the bolt (14) through the central slot.
 3. Load-engaging device according to claim 1, characterized by an universal joint (19) having a first lug (18) with a through bore retained by the bolt (14) through the central slot (12), as well as a fork having legs (20) placed transversely of said first lug (18) with mutually aligned bores extending through the legs (20) of said fork for receiving a bolt (21), to which a second lug (22) is secured between the legs (20) of the fork, said second lug (22) having an eye (23) for engaging a connecting means.
 4. A load-engaging device for lifting an element from which projects a lifting bolt having a head and a stem, comprising:(a) a body (6) having a partial spherical surface; (b) a manipulating arm (7) protruding from the body (6); (c) the body (6) having a receiving slot (10) adapted to receive the head (2) and part of the stem (3) of the lifting bolt, the receiving slot having a head receiving cut-out with a width greater than the width of the head (2) of the lifting bolt, the receiving slot having a stem receiving slot with a width greater than the width of the stem of the lifting bolt, the stem receiving slot is in communication with the head receiving cut-out; (d) a connection slot (12) opening into the receiving slot (10); and (e) attachment means which extend within the region of the connection slot (12) for attaching a connecting means to the body.
 5. The load-engaging device of claim 4, wherein the receiving slot has a retaining position.
 6. The load-engaging device of claim 5, wherein the attachment means extends within the region of the slot (12) eccentrically in the body (6).
 7. The load-engaging device of claim 6, wherein the attachment means is substantially diametrically opposite the retaining position for the lifting bolt.
 8. The load-engaging device of claim 7, wherein the attachment means comprises mutually aligned bores (13) for receiving a bolt (14).
 9. The load-engaging device of claim 4, wherein the connection slot (12) extends centrally and substantially diametrically in the body (6).
 10. The load-engaging device of claim 4, wherein the receiving slot (10) extends through approximately 180 degrees along the partial spherical surface of the body.
 11. The load-engaging device of claim 4, wherein the body has a partially spherical surface limited by parallel segmenting planes. 